This invention relates to a winding device for threads from V-creels, from the bobbins of which the threads are drawn off via pre-looping bars and through a comb, and are wound up on a winding shaft of the winding device, with the pre-looping bars being wound with more threads near the winding device and fewer threads at a distance from it, and with their degree of looping being centrally adjustable, with at least one measuring device being located beyond the comb in the running direction of the threads for determining the thread tension in threads, and with the central adjustment of the pre-looping bars being controllable according to the result of measurement.
The winding device pulls the threads off of bobbins that are set on bobbin spindles of bobbin stations of the bobbin creel. They ordinarily have to be braked to produce the thread tension or thread tensile force necessary for proper winding. However, the thread running speed can become so great that the braking, of the threads when being taken off of the bobbins is no longer necessary. Above all, the atmospheric frictional resistance of the thread can become so great that additional braking is unnecessary. This is especially true for V-creels. The thread tension produced by the atmospheric frictional resistance of the thread, however, depends on the length of the thread between the bobbin station and the winding device. In the case of long creels this has the result that the threads that come from the end of the creel have greater thread tension on the winding device than the threads that come from the beginning of the creel. To compensate for these differing thread tensions, the pre-looping bars are used so that there is stronger looping of the bars by the threads at the beginning of the creel but weaker looping at the end of the creel. Accordingly, the thread tensions are affected differently. In particular, the thread tensions of the threads running off from the beginning of the creel are increased so that they are equal in all of the threads running to the winding device.
Controlling of the thread tensions of the threads results from their friction on the pre-looping bars. The friction of the threads rubbing approximately tangentially on the pre-looping bars depends on their material and on the running speed of the threads. Even using the same material with different thickness provides different thread tensions. Readjustment of the pre-looping bars is then necessary to achieve matching. The more the threads differ in material and speed, the more difficult such matching becomes. Automatic readjustment is not possible since the entire pre-looping bar unit can be adjusted only as a whole.
There is a need for adjustment also with different winding devices. This applies to all installations in which the threads to be rewound are drawn off with thread braking by a thread clamp for each, that clamps the threads in case of shutdown or thread breakage. There is also a need for adjustment when several winding shafts are to be wound from one set of bobbins, since additional thread tensions result from the decreasing bobbin diameters and the increased rotation of the thread around the bobbin resulting from this. From the winding of one shaft to the winding of the next shaft, a thread tension increase occurs that has to be compensated for, so that the wound diameter of the second shaft does not become smaller than that of the first.
A winding device with the features mentioned at the outset is disclosed by DE 9 306 680 U1. It is possible with the braking bars to control the running resistance of the threads by adjusting these rods relative to one another to vary the looping. Such adjustment, however, cannot occur predominantly automatically because the overall adjustment and/or the central adjustment of the pre-looping bars cannot take into consideration the fact that the thread tensions change differently from the end of the creel to the beginning of the creel depending on the material and thread running speed. The same also applies to the winding device of DE 40 02 545 A1, which relates to a winding device with the initially mentioned features and in which a control unit serves to maintain a constant tension of running threads from the beginning to the end of the warping frame operation.